| 摘要 |
1,092,411. Piston seals. DURIRON CO. Inc. Feb. 12, 1965 [Feb. 14, 1964], No. 6281/65. Headings F2B and F2T. Piston sealing means comprises a sealing member 30 of fluorocarbon material, e.g. P.T.F.E., which is secured to the piston or cylinder against axial movement thereon by annular crests 20 and grooves 25 on the piston or cylinder engaging complementary grooves 32 and crests 33 on the member 30, the grooves 25 having root portions spaced a small distance from the crests 33 to provide expansion spaces 35 into which the material of the member can expand when heated. The areas of the member 30 radially aligned with the crests 20 provide high pressure sealing areas whilst those radially aligned with the spaces 35 form low-pressure sealing areas. In a modification (Fig. 7) the member (75) is urged outwardly over a part of its axial length by a resilient 0-ring (70) housed in a groove in the piston. The sealing member may be fitted on the piston by placing a seal blank (55, Fig. 5) of P.T.F.E. in the form of a cup over the grooved end of the piston (59), heating them together under radial pressure in a mould (60) so that the crests 20 penetrate the blank which partially enters the grooves 25 and subsequently cooling the assembly with the blank pressed against the piston. The end (56) of the blank may be removed or left as a coating on the piston crown.
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